From 1f747b9132c57d0a14e1f3bbb03e19c7fa4e2721 Mon Sep 17 00:00:00 2001
From: Daniel Bertalan <dani@danielbertalan.dev>
Date: Sun, 27 Aug 2023 12:13:47 +0200
Subject: [PATCH] CMake: Use `CMAKE_POSITION_INDEPENDENT_CODE` instead of
 explicit `-fpic`

This makes CMake pass `-fpie` instead of `-fpic` to the compiler when
building the Kernel and userland *executables*. This allows the compiler
to make certain optimizations based on the fact that the code will be
used in an executable, such as not having to emit `.localalias` symbols.
This leads to a 450 KiB decrease in the size of the Kernel binary.
---
 CMakeLists.txt                            | 2 --
 Meta/CMake/serenity_compile_options.cmake | 2 ++
 Userland/DynamicLoader/CMakeLists.txt     | 2 +-
 3 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/CMakeLists.txt b/CMakeLists.txt
index 09570e7dd17..13bc7d23475 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -167,8 +167,6 @@ add_link_options(LINKER:-z,text)
 add_link_options(LINKER:--no-allow-shlib-undefined)
 
 add_compile_definitions(SANITIZE_PTRS)
-set(CMAKE_CXX_FLAGS_STATIC "${CMAKE_CXX_FLAGS} -static")
-set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -pie -fpic")
 
 if (ENABLE_COMPILETIME_FORMAT_CHECK)
     add_compile_definitions(ENABLE_COMPILETIME_FORMAT_CHECK)
diff --git a/Meta/CMake/serenity_compile_options.cmake b/Meta/CMake/serenity_compile_options.cmake
index 6bab7b77085..7cc39f5a25d 100644
--- a/Meta/CMake/serenity_compile_options.cmake
+++ b/Meta/CMake/serenity_compile_options.cmake
@@ -27,6 +27,8 @@ add_link_options(-fstack-protector-strong)
 
 add_compile_options(-g1)
 
+set(CMAKE_POSITION_INDEPENDENT_CODE ON)
+
 if (CMAKE_CXX_COMPILER_ID STREQUAL "GNU")
     add_compile_options(-Wno-maybe-uninitialized)
     add_compile_options(-Wcast-align)
diff --git a/Userland/DynamicLoader/CMakeLists.txt b/Userland/DynamicLoader/CMakeLists.txt
index e76ff69b680..469054966e0 100644
--- a/Userland/DynamicLoader/CMakeLists.txt
+++ b/Userland/DynamicLoader/CMakeLists.txt
@@ -30,7 +30,7 @@ add_definitions(-D_DYNAMIC_LOADER)
 
 set(SOURCES ${LOADER_SOURCES} ${AK_SOURCES} ${ELF_SOURCES} ${LIBC_SOURCES1} ${LIBC_SOURCES2} ${LIBC_SOURCES3} ${LIBSYSTEM_SOURCES})
 
-set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -fno-rtti -nostdlib -pie -fpic -DNO_TLS")
+set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -fno-rtti -nostdlib -pie -fpie -DNO_TLS")
 
 if ("${SERENITY_ARCH}" STREQUAL "aarch64")
     # On aarch64 the stack protector would be accessed before the Loader can relocate itself.